These commands will create the EFI partition. Double-check everything by typing list vol. You should see a 200 MB partition. You now need to assign it a letter. Do this by typing assign b:, then list vol again to see what letter has been assigned.

Now this is done you need to copy the boot files to this newly created partition:

bcdboot C:\Windows /l en-gb /s B: /f ALL

Note: you must replace C: with the drive letter of the partition that contains Windows, and B: with the letter assigned to the EFI partition you just created.